Thin film cobalt-platinum (CoPt) and cobalt-platinum-phosphorus (CoPtP) alloys have been known as potential perpendicular recording materials for use in hard disk drives due to their high magnetocrystalline anisotropy and magnetic saturation. Specifically, an ordered phase of Co50Pt50 shows very high coercivities (>10 kOe). Besides application in the magnetic recording industry, recently CoPt-based materials have been assessed to have huge potential for application in microelectromechanical systems (MEMS) due to their high energy-product as required by magnetic microactuators. The energy-product indicates the energy that a magnetic material can supply to an external magnetic circuit when operating at any point on the material's demagnetisation curve. MEMS technology has made use of semiconductor manufacturing technology for the fabrication of micro- and nano-devices.
Usually, thin films (sub-micrometer) of cobalt-platinum are fabricated by vacuum deposition processes. However, the operating cost of a vacuum deposition process may be high. Recently, electroplating is being used as an alternative method.
Attempts have been made to fabricate Co-based films using electroplating processes, the thickness of the film usually having been limited to a thickness of less than 10 μm. Further, the thermal stability of the films has not been previously investigated. The thermal stability of films is essential in assessing the possible use of the films in various devices, especially MEMS devices. In particular, the film has to be of sufficient thickness to meet the requirement of the MEMS device it is to be used in.
In view of the above considerations, there is a need to develop a new material of sufficient thermal stability and one which is capable of thick film deposition by a suitable method.
An object of the present invention is to address the problems set out above.